Sealed switch for strong currents



Feb. 22, 1966 B. DAL BIANCO ETAL 3,236,965

SEALED SWITCH FOR STRONG CURRENTS Filed Aug. 16, 1965 F/GJ nventor B. DAL BIA/V00 M. SCA TA 730) AH ney United States Patent Ofiice SEALED SWITCH FOR STRONG CURRENTS Bruno Dal Bianco, Milan, and Mario Scata, Monza,

Milan, Italy, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed Aug. 16, 1963, Ser. No. 302,585 Claims priority, application Italy, Aug. 31, 1962, Patent 678,587 4 Claims. (Cl. 200-87) The object of the present invention is a sealed switch for strong currents. A switch of this kind has been already revealed in our pending application in the United States, No. 302,583, filed on August 16,1963, and the present invention has the object to modify the preceding type of switch to obtain a new device which incorporates the known principle of the stored resilience in a metallic blade subjected to a mechanical temporary deformation, as already used in microswitch devices.

The purpose of the present invention is then to provide a switch for a relay suitable for switching currents of greater intensity than that carried by the device revealed in the above mentioned patent and suitable to be used with higher operating voltages.

It is known that the main factor preventing the formation of an electric are between the contacts and then the wear thereof is to eliminate rebound vibrations or the decelerating forces present in the switching arm. The use of the above cited principle makes possible to close and open instantaneously the contacts by moving the movable arm carrying the double button to and far from the stationary ones removing or reducing the wear of the contact buttons. Moreover by enclosing the contacts and the magnetic members for the actuation thereof in a sealed vessel, air evacuated and or filled with an inert gas, those are safeguarded from the corrosion or deterioration assuring long life and reliability in the switching operations. The action of an inert gas into the envelope reduces or eliminates the are between the contacts so that this device could be used safely in the mines and in the rooms subjected to explosives gases.

The use of the principle of the snap, silient blade to which is secured makes the device also not influenced fore suitable to be installed aboard motor vehicles and in the apparatus submitted to shocks and vibrations.

In a preferred form of the present invention a pair of stationary magnetic electrodes cooperate with a movable magnetic armature to which is secured the snap blade carrying the movable contact.

By the action of a magnetic field near the envelope containing said magnetic members the magnetic contact is snapped from a first position on which it was previously switched to the other one on which it strongly engages the stationary contact.

The invention will be better understood from the following description of two embodiments given by way of example and illustrated in the acompanying drawings, in which:

FIG. 1 shows an enlarged view of a longitudinal cross section of a switch including all the features, according with the invention;

FIG. 2 is a side view of the switch illustrated in FIG. 1;

FIG. 3 is an enlarged view of a longitudinal cross section of an alternative embodiment of the switch of FIG. 1;

FIG. 4 is a side view of the switch of FIG. 3.

Referring now to the drawing and particularly to FIG. 1 a magnetically controlled switch structure is enclosed in a metallic container 1, of non-magnetic material (ii. of cylindrical form) closed at one end 2 and open at the opposite end thereof to accommodate a base or metal plug inherent to rethe movable contact by shocks and there- I ture and which faces parallel to the 3,236,965 Patented Feb. 22, 1966 3, which will be sealed to container 1 by welding or other known sealing methods. Plug 3 is provided with insulating insertions 4 of glass or ceramic to insulate and seal the connecting leads 5, 6, 7 forming part of the metallic structure of the switch, which protrude outside from side container to provide soldering terminals, for the external circuit (f.i. a printed circuit) or pins to plug-into suitable socket; and extending internally to the container 1 to support, as it will be described later, the various members, forming the switching structure.

Inside the container 1, the lead 5 is flattened to place and weld thereon the end of a magnetic plate 8 the other end thereof carrying non-magnetic plate 9 which is welded to the latter. A magnetic member 10 has a plane portion welded to plate 9 in such a way that it lies in the plane of plate 8, leaving a gap between the facing edges of plate 8 and member 10 for the purpose described later.

Magnetic member 10 is formed by a reversed L bent plate, with an end 11 tapered, to form a tooth directed toward base 3. To the internal shorter branch of L member is welded the end 12 of a flat spring, suitably bent, an upper part thereof coming in contact with the top of tooth 11 (FIGS. 1 and 2). This flat spring extends longitudinally within the envelope and is provided at the other end with a double contact button 14. The flat spring is of the microswitch type and is provided with a slot 15 containing an auxiliary corrugated flat spring 16 (FIG. 1) precompressed. In a suitable point of said fiat spring 13, perpendicularly thereto, is welded the projection 17 of a flat disc 18 of magnetic material which acts as an armaplane formed by magnetic pieces 8-10 from which it is slightly spaced and positioned at the center of the separation between pieces 810.

A first stationary contact button 19 is secured to the end of lead 6 and a second stationary contact button 20 is welded to the end of lead 7, both protruding inside the container 1 from the base 3, in alignment therebetween and with the double movable contact button 14, leads 6 and 7 being insulated from said base.

Referring to FIG. 1, an external electric circuit is completed through lead 5, plate 8, strip 9, magnetic member 10, resilient spring 13, double button 14, stationary button 19 and lead 6. When an external magnetic field is applied; which can be created by a coil surrounding the container 1, the disc or armature 18 and pieces 8-10 will be drawn together, consequently flat spring 13 will be subjected to an inversion of its resilient action causing double button 14 to snap from contact 19 to contact 20 on which it will exert a constant pressure provided by the resilient force inherent to the material increased by the effect of the small corrugated auxiliary spring 16.

An electric circuit will now be completed through 5, 8, 9, 10, 13, 14, 20, 7. The tooth 11 provided on member 10 was previously adjusted to increase the pressure exerted by spring 13, via button 14 toward button 19, bending tooth 11 laterally in the stage before the introduction of the metallic structure into the envelope.

When no magnetic field is present around the envelope, the flat spring 13, helped by the small corrugated spring 16 will cause button 14 to snap again toward button 19.

FIG. 3 illustrates a modification of part of the magnetic structure in alternative to that shown in FIG. 1 to operate the resilient flat spring of microswitch type.

From an inspection of the magnetic structure shown in FIG. 3 the members of which bear the same reference numbers of FIG. 1 with the exception of the parts differing therefrom, it will be observed that lead 5 is flattened to receive by welding an end of a plate 8 of magnetic material, to the other end of which is welded, on the same side of terminal 5, a member 21, formed by a strip of non magnetic material bent in the form of a reversed L, the end 22 of which incorporates a tooth similar to that shown in FIG. 1. To the inner face of the shorter arm of member 21 is welded an end 12 of a flat spring 23, suitably bent, part of which is contacting tooth 22 of member 21, for the scope already explained in connection with the preceding example. Flat spring 23 is provided, along the longitudinal direction thereof, with two ribs 25, 26 (visible in FIG. 4) and, at its free end, with a double contact button 14. To flat spring 23 there is also welded, in a suitable point thereof, a magnetic member 24 of any shape, but having a plane face in front and parallel to the plane portion of the magnetic piece 8. A stationary contact button 19 is welded to the end of lead 6 and a second stationary button 20 is welded to the end of lead 7, both leads projecting inside container 1 from base 3 in alignment therebetween and with the double contact button 14; all the leads being insulated from the base 3. The adjustments of the air gap and the contact pressure between the ditfer'ent members is made before inserting the structure inside the envelope 1. The resilient flat spring 23 which is shaped so that double button 14 thereon exerts a pressure against stationary button 19, is further loaded by slightly bending tooth 22 inward toward member 21. With this operation also air-gap between magnetic members 24-8 is drawn for the best sensitivity of operation.

An external electric circuit is therefore completed through lead 5, magnetic member 8, non-magnetic member 21, resilient spring 23 double contact button 14, stationary contact 19, and lead 6.

When an external magnetic field is applied near the envelope 1 the magnetic member 24 and magnetic member 8 will be drawn together and thereby the ribbed spring 23 will be subjected to an inversion of its resilient force causing double button 14- to snap from contact 19 to contact 20. An electric circuit is now completed through 5, 8, 21, 23, 14, 20, 7.

While the principles of the present invention have been described above with reference to two specific examples of embodiments, it will be clear to those skilled in this art that other modifications and variations in the design could be made without however departing from the scope and the spirit of the present invention.

What is claimed is:

1. A switching relay comprising: I

a non-magnetic envelope closed at one endand sealed by a plug at the other,

first, second and third conductive leads extending through said plug and sealed thereto to provide separately insulated contact leads extending both inside and outside said non-magnetic envelope, first and second magnetic members,

the first one of said conductive leads supporting said first magnetic member within said envelope, first and second single faced contact buttons,

said second one of said conductive leads supporting the first one of said single faced contact buttons within the envelope, said third one of said conductive leads supporting the second one of said single faced contact buttons within the envelope causing it to occupy a position facing the first contact button,

a curved member having first and second ends,

said first magnetic member supporting a first end of said curved member Within the envelope,

a resilient fiat spring of the microswitch type having first and second ends,

said second end of said curved member supporting the first end of said resilient flat spring,

said second end of said flat spring supporting a double faced contact button in a position between said first and second single faced contact buttons,

said flat spring supporting said second magnetic member at a point between said first and second ends in near proximity to said first mag-netic member,

said fiat spring being mechanically biased at said first end to hold one face of said double faced contact button in contact with said first one of said single faced contact buttons, and

said second magnetic member cooperating with said first magnetic member in the presence of a magnetic field to cause said flat spring to change its stored state of resilience to snap the second face of said double faced contact button into contact with said second one of said single faced contact buttons, said snap causing.

" 1, in which means is provided for adjusting contact pressure between the double faced contact button and said first single faced contact button,

said means for adjusting contact pressure including an extension of said curved member,

said extension being bendable to engage said flat spring to adjust the mechanical bias of the flat spring and thus said contact pressure.

References Cited by the Examiner UNITED STATES PATENTS 2,037,535 4/1936 Rankin 200-87 2,180,701 11/1939 Wilson 20087 2,242,636 5/1941 Wilson 20087 2,693,520 11/1954 Bruno 200-67 X 3,118,987 1/1964 Clements 20087 FOREIGN PATENTS 894,378 4/1962 Great Britain.

60,759 4/1939 Norway.

ROBERT K. SCHAEFER, Acting Primary Examiner.

BERNARD A, GILHEANY, Examiner, 

1. A SWITCHING RELAY COMPRISING: A NON-MAGNETIC ENVELOPE CLOSED AT ONE END AND SEALED BY A PLUG AT THE OTHER, FIRST, SECOND AND THIRD CONDUCTIVE LEADS EXTENDING THROUGH SAID PLUG AND SEALED THERETO TO PROVIDE SEPARATELY INSULATED CONTACT LEADS EXTENDING BOTH INSIDE AND OUTSIDE SAID NON-MAGNETIC ENVELOPE, FIRST AND SECOND MAGNETIC MEMBERS, THE FIRST ONE OF SAID CONDUCTIVE LEADS SUPPORTING SAID FIRST MAGNETIC MEMBER WITHIN SAID ENVELOPE, FIRST AND SECOND SINGLE FACED CONTACT BUTTONS, SAID SECOND ONE OF SAID CONDUCTIVE LEADS SUPPORTING THE FIRST ONE OF SAID SINGLE FACED CONTACT BUTTONS WITHIN THE ENVELOPE, SAID THIRD ONE OF SAID CONDUCTIVE LEADS SUPPORTING THE SECOND ONE OF SAID SINGLE FACED CONTACT BUTTONS WITHIN THE ENVELOPE CAUSING IT TO OCCUPY A POSITION FACING THE FIRST CONTACT BUTTON, A CURVED MEMBER HAVING FIRST AND SECOND ENDS, SAID FIRST MAGNETIC MEMBER SUPPORTING A FIRST END OF SAID CURVED MEMBER WITHIN THE ENVELOPE, A RESILIENT FLAT SPRING OF THE MICROSWITCH TYPE HAVING FIRST AND SECOND ENDS, SAID SECOND END OF SAID CURVED MEMBER SUPPORTING THE FIRST END OF SAID RESILIENT FLAT SPRING, SAID SECOND END OF SAID FLAT SPRING SUPPORTING A DOUBLE 